Methods for restoring blood flow within blocked vasculature

Abstract

The devices and methods described herein relate to clearing of blockages within body lumens, such as the vasculature, by addressing the frictional resistance on the obstruction prior to attempting to translate and/or mobilize the obstruction within the body lumen.

We claim: 
     
       1. A method comprising:
 advancing a catheter through an obstruction within a blood vessel, the catheter containing an obstruction removal device having an expandable structure located at the end of a leading member, the expandable structure having a central longitudinal axis and comprising a plurality of filaments, wherein the expandable structure includes an intermediate portion extending between a proximal end and a distal end, and wherein the intermediate portion includes first and second regions, 
 deploying the obstruction removal device from the catheter such that the expandable structure expands to a deployed state, wherein, in the deployed state, the filaments of the expandable structure converge radially inwardly toward the central longitudinal axis to meet at the first and second regions; 
 withdrawing the catheter relative to the expandable structure such that the intermediate portion self-expands within the obstruction to engage the obstruction via the first and second regions; 
 and withdrawing the obstruction removal device and obstruction from the blood vessel. 
 
     
     
       2. The method of  claim 1 , further comprising positioning the obstruction removal device across the obstruction such that the obstruction removal device is initially offset from a longitudinal axis of the obstruction. 
     
     
       3. The method of  claim 1 , wherein withdrawing the catheter includes withdrawing the catheter relative to the obstruction removal device such that the distal end of the obstruction removal device remains distal to the obstruction. 
     
     
       4. The method of  claim 1 , further comprising allowing the intermediate portion to embed into the obstruction. 
     
     
       5. The method of  claim 1 , further comprising allowing the intermediate portion to embed into the obstruction without dislocating or mobilizing the obstruction within the blood vessel. 
     
     
       6. The method of  claim 1 , wherein the obstruction removal device further comprises a surrounding portion attached to the distal end of the obstruction removal device and further comprising covering the obstruction with the surrounding portion. 
     
     
       7. The method of  claim 6 , wherein the surrounding portion comprises a structure selected from the group consisting of a basket, a filter, a bag, a coil, a helical wire structure, a mesh, a corrugated sheet, braided wires, a single wound wire, a plurality of crossing wires, a tube, a membrane, a filled tube, a solid wire, a casting, and a film. 
     
     
       8. The method of  claim 1 , wherein the obstruction removal device is fabricated from a process selected from the group consisting of a photochemical etching, mechanical drilling, weaving, braiding, and laser cutting. 
     
     
       9. The method of  claim 1 , further comprising advancing the catheter adjacent to the obstruction such that the obstruction removal device is advanced through the catheter to the obstruction. 
     
     
       10. The method of  claim 1 , further comprising withdrawing at least a portion of the obstruction removal device within the catheter and removing the catheter from the vessel. 
     
     
       11. The method of  claim 1 , wherein the obstruction comprises a blood clot, plaque, cholesterol, thrombus, a naturally occurring foreign body, a non-naturally occurring foreign body or a combination thereof. 
     
     
       12. The method of  claim 1 , further comprising expanding the vessel adjacent to the obstruction to decrease a friction between the vessel and the obstruction. 
     
     
       13. The method of  claim 1 , wherein the intermediate portion forms a shaped section about the obstruction between the first and second regions. 
     
     
       14. The method of  claim 1 , wherein the proximal and distal ends of the expandable structure are expanded towards the vessel wall when the first and second regions of the intermediate portion converge radially inwardly. 
     
     
       15. The method of  claim 1 , wherein each of the filaments are prevented from moving apart from other ones of the filaments where the filaments meet along the first and second regions. 
     
     
       16. A method comprising:
 advancing an obstruction removal device through an obstruction within a blood vessel, the obstruction removal device including an expandable structure comprising a plurality of filaments, the expandable structure having a central longitudinal axis and an intermediate portion, wherein the intermediate portion extends between a proximal end and a distal end and has first and second regions; 
 deploying the expandable structure to a deployed state such that (i) the filaments converge radially inwardly toward the central longitudinal axis to meet within each of the first and second regions, and (ii) the intermediate portion of the expandable structure engages the obstruction between the first and second regions; and 
 withdrawing the obstruction removal device and obstruction from the blood vessel to improve blood flow in the blood vessel. 
 
     
     
       17. The method of  claim 16 , wherein the intermediate portion forms a shaped section about the obstruction between the first and second regions. 
     
     
       18. The method of  claim 16 , further comprising positioning the obstruction removal device across the obstruction such that the obstruction removal device is initially offset from a longitudinal axis of the obstruction. 
     
     
       19. The method of  claim 16 , wherein the expandable structure of the obstruction removal device is self-expanding. 
     
     
       20. The method of  claim 16 , wherein the obstruction removal device is fabricated from a process selected from the group consisting of photochemical etching, mechanical drilling, weaving, braiding, and laser cutting. 
     
     
       21. The method of  claim 16 , further comprising withdrawing at least a portion of the obstruction removal device within a catheter and removing the catheter from the vessel.